The present invention relates generally to three-dimensional mesh shapes and, more particularly, to the filleting and rounding of sharp edges of such mesh shapes.
Many applications, such as medical and industrial design and manufacturing applications, involve manipulating and editing digital models of objects that have been scanned via, illustratively, 3D scanning of the object. As one skilled in the art will understand, such digital models typically consist of a point cloud representation of the object, with the number of points depending upon the resolution of the scanning process. Once such a point cloud representation has been obtained, the surface of the object is, in many instances, then approximated by connecting the points of the point cloud to form a mesh of triangles on the surface of the point cloud representation. This surface may then be edited by using, for example, computer aided design (CAD) software programs or similar specialized image manipulation software programs.
Many editing operations are extremely well known and are integrated into most computer aided design (CAD) software programs. Two illustrative and well-known operations, referred to herein as filleting and rounding, are frequently applied to digital models of a three dimensional shape to smooth out, or round, a sharp edge of the model into a smoother edge. FIG. 1 shows an illustrative example of such filleting and rounding. Referring to that figure, shape 101 is, illustratively, a cross section of a three-dimensional object such as an aforementioned model of a shape stored in computer memory. Shape 101 has, for example, corner 102 and corner 103 for which rounding/filleting are desired to smooth the corners. By removing corners 102 and 103 and blending in the adjacent surfaces, smoothed surfaces 104 and 105 result. Surface 104 is referred to herein as a “rounded” surface, since that surface is convex. On the other hand, surface area 105 is referred to herein as “filleted”, since that surface is concave.
In many situations, the editing of a triangle mesh model, such as the aforementioned model created from connecting the points obtained by 3D scanning of an object, will result in sharp edges. For example, FIG. 2 shows an illustrative 3D shape 201 that has been edited by cutting the shape 201 with cutting plane 202. Such a cutting operation produces a sharp edge 203 for which, illustratively, a rounded edge may be desirable.